The Securities and Exchange Commission (SEC) is the primary body responsible for enforcing insider trading laws in the United States. These regulations are largely based on the Securities Exchange Act of 1934 and subsequent rules, with the goal of ensuring a fair and transparent market for all investors.

Key Regulations and Theories:
The core of US insider trading law is Rule 10b-5, which falls under Section 10(b) of the Securities Exchange Act. This rule broadly prohibits any fraudulent or deceptive practices in connection with the purchase or sale of securities. Insider trading is considered a violation of this rule.

There are two main legal theories used to prosecute insider trading:
  • Classical Theory: This applies when a company's officers, directors, or other employees trade on material, non-public information ( what we call as UPSI in India) in breach of a fiduciary duty to the company's shareholders. "Material" information is any information a reasonable investor would consider important in making an investment decision.
  • Misappropriation Theory: This covers individuals who are not traditional company insiders but who nonetheless trade on confidential information. This theory states that it is illegal for a person to misappropriate information from the source and then use it to trade securities. For example, a lawyer who learns about an upcoming merger from a client and then trades on that information would be in violation, even though they are not an employee of the company being acquired.

The SEC also established Rule 10b5-1, which provides an "affirmative defense" for insiders. This rule allows company insiders to set up a predetermined trading plan in advance, while not in possession of material non-public information. This plan then allows them to make trades automatically, even if they later acquire such information, as long as the plan was set up in good faith.

Penalties for Violations:
Insider trading can result in both criminal and civil penalties.
  • Criminal Penalties: The Department of Justice can prosecute individuals for insider trading, leading to significant fines (up to $5 million for individuals and $25 million for entities) and imprisonment for up to 20 years.
  • Civil Penalties: The SEC can bring a civil action, which may result in a fine of up to three times the profit gained or loss avoided from the illegal trade. Violators may also be required to disgorge (return) any profits made and may be barred from serving as an officer or director of a public company.

The SEC actively monitors trading activity for any suspicious behavior to detect and prosecute violations, regardless of the size of the trade.